New Defensive Missiles Protect U.S. Against Rogue Attacks

America's missile shield is designed to destroy incoming ballistic warheads with interceptors. President-elect Obama's leading contenders for the job as Secretary of Defense have this week sent signals that the next administration would continue the Missile Defense Agency program, and Obama expressed support for it during his campaign. To learn more about missile defense, PM visited an Alaskan Army base where soldiers keep defensive missiles locked and loaded in case a rogue nation makes its move. But will the system work?

The sign next to the door is not an omen. It shows a bright red figure in a protective suit, the kind of full-body gear you might wear when handling dangerous pathogens. Or, in this case, when entering a building housing an operational three-stage ballistic missile, freshly plucked from its silo. The sign is a reminder of the danger posed by the nearby missile's fuel tank, which can release a toxic plume if damaged. Through the door is a small room filled with pipes, gauges, air-quality sensors and another doorway. "Okay, get ready," an Army public-affairs officer says before leading the way. "This is one of those 'wow' moments."

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The door opens to reveal a 58-ft missile, its nose aimed at whomever enters the room. The missile, a ground-based interceptor (GBI), is not designed to deliver nuclear weapons, but rather to stop them while they are in flight. If North Korea or Iran launches an intercontinental ballistic missile (ICBM) at the United States, one or more of these GBIs are ready to take flight.

When an interceptor escapes the Earth's atmosphere, its booster stacks fall away, leaving a tiny spacecraft to finish the suicide mission. This 152-pound, 55-in.-long kill vehicle hurtles through space, using lateral thrusters to steer toward a blunt-force collision with the enemy warhead. "You've probably heard it said that we're trying to hit a bullet with a bullet," says Col. George Bond, who coordinates Missile Defense Agency (MDA) operations in the Alaska region. "But this is really a brilliant bullet, backed by some of the most powerful radars in the world and a very sophisticated communication system."

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Although the radar platforms and command centers that track enemy missiles are positioned around the world, the backbone of ICBM defense is here at Fort Greely, an Army base more than 100 miles southeast of Fairbanks, Alaska. All but four of the 30 planned ground-based interceptors fielded by the MDA will be located at Greely; the others will be stationed at Vandenberg Air Force Base in California. GBIs are the only way the U.S. can stop ICBM warheads in space from reaching their targets. From Alaska, interceptors can be sent over the Arctic to destroy enemy missiles headed for either coast of the continental United States.

It has been 25 years since President Ronald Reagan first proposed a missile shield, dubbed Star Wars, to counter the Soviet Union's nuclear arsenal. The Soviets, though, had the ability to overwhelm such defenses with the sheer number of their ICBM-launched warheads. Now, as ballistic-missile technology proliferates, potentially hostile nations like Iran and North Korea are gaining the ability to launch long-range ballistic missiles at the U.S. coastline, overseas military bases or American allies. But these rogue regimes do not yet have Soviet-size stockpiles of warheads or missiles. This more limited threat enables a functional missile shield--based on the ground, instead of in orbit--to become a reality.

Some analysts question whether the system would be effective against even a lone rogue missile, and dispute whether fear of such an attack requires spending billions of dollars a year. Others argue that 100 percent effectiveness is not the issue. Here at Greely, under the strangely jaundiced lights of a room that's colder than the 57-degree August day outside, is the core of a system that may not necessarily be called on to intercept anything. Its job is simply to exist and thereby prevent attacks. Like the 25 other GBIs here at the base, the missile I'm looking at is a technologically advanced, multimillion-dollar deterrent.

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How to Thwart Armageddon

Peering inside an empty Missile Silo, it is hard to avoid a moment of panic. It is irrational, like flinching at an unloaded gun. But if a nuclear launch against America occurred, and the GBI loaded into this silo fired in response, there would be at least one immediate casualty: me. Ducking into the adjacent underground trailer, which is filled with electronics and climate-control gear, would offer little protection during a launch if the door was not properly sealed. Searing gases from the rocket plume would flood the room, damaging the hardened equipment and cooking me alive. "It's not like a submarine, which comes out with a cold launch, and the boosters kick in when it's up out of the water," Bond says. "This is a hot launch, so there's a lot of exhaust coming right back down that hole."

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Since the missile normally loaded into this silo is undergoing a routine check, I can stick my head into the launch tube. If it weren't so sterile, it could be an abandoned well or industrial access tunnel. The dim light provided by a handful of naked light bulbs reveals a network of pipes and control leads that would be severed, and then incinerated, by an interceptor launch. Bond tells me that GBI silos aren't designed for rapid-fire use or a protracted shooting war. Repairing a used silo takes days, and building a new GBI to drop into it takes even longer. "This truly is a limited capacity," he says.

The MDA is designing a layered defense that could defeat a missile in each of the three phases of its flight--boost, midcourse and terminal (see diagram, opposite). The lack of advanced warning makes a boost-phase interception difficult, and the speed of an inbound warhead--as fast as 10,000 mph--makes terminal defenses a technical nightmare. The time in space during the midcourse phase provides the best opportunity to stop an ICBM, so the U.S. government is eagerly fielding GBIs that strike above the atmosphere.

Here's how the interceptors are supposed to work. Let's say that North Korea risks annihilation by firing a pair of two-stage Taepodong-2 missiles at the continental United States. Early warning satellites pick up a pair of fast-moving, white-hot infrared signatures arcing away from North Korea. Their location is passed on to a network of terrestrial radar, from land-based arrays to Aegis naval vessels equipped with SPY-1 radar. All of the data streams back to the nerve center of the Ballistic Missile Defense System, a command center in Colorado Springs, Colo. Computers rapidly calculate the incoming trajectory: The nukes are heading toward San Francisco.

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Staff in Colorado Springs scramble to draw up a battle plan to determine how many GBIs are ­needed, where the launch vehicles will fire from--Greely or Vandenberg--and what their initial trajectories will be. By the time the interceptor launch crew at Greely or Vandenberg gets its orders, both enemy missiles have escaped the atmosphere and entered the midcourse stage of flight. The booster stacks have fallen away, leaving a pair of smaller re-entry warheads to float through space for as long as 20 minutes, with little or no rocket burn. It's the orbital equivalent of running silent. To keep an eye on the twin targets, the MDA calls on some of the most powerful radars in the world, including the Sea-Based X-Band Radar, a massive, dome-shaped array mounted on a mobile, modified oil rig. Provided with the locations of the targets, five-man launch teams in Greely or Vandenberg now send interceptors screaming out of the silos.

When the GBIs reach space, the nose-cone shrouds detach and the exoatmospheric kill vehicles (EKV) emerge, ejected into orbit at 15,000 mph in the general direction of the warhead. The EKVs establish contact with the closest terrestrial-based control terminal (Vandenberg, Greely or Colorado Springs) to get the updated location of the targets. The powerful radar also provides critical information to discriminate decoys, such as Mylar balloons, and other spoofing countermeasures from real warheads. Using the latest position of its target, the kill vehicles tweak their trajectories with thruster bursts. Forward-facing visible-light sensors onboard the EKVs allow them to make last-minute adjustments. Each kill vehicle steers into the speeding target at a combined velocity of 4 miles per second, pulverizing both EKV and target into a field of orbital debris.

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But if the EKVs miss, San Francisco is less than a minute away from immolation. The MDA is working on aircraft-mounted lasers and other systems to hit missiles as they launch, and advanced mobile launchers that could destroy incoming warheads. For now, GBIs are the best operational weapon we have against ICBMs.

Which leaves a vital question: Does the system work? That's a matter of fierce debate, and the success rate of tests is mixed. Since 1999, the MDA's strategic defense system has passed seven out of 12 hit-to-kill tests. But in the six years since President George W. Bush pushed for deployment to counter North Korean missiles, only two of the ground-based interceptor tests have been successful. According to Wade Boese, research director for the Arms Control Association, a nonprofit organization based in Washington, D.C., at least some of the MDA's successful intercepts involved tests where the location and planned trajectory of the target were known in advance, as opposed to being gleaned from the radar network. "You have to be honest about the limitations of testing," Boese says. "It's like taking a kid to a batting cage, letting him hit against a machine that throws in the same spot, at the same speed. You can't expect him to go out and hit against a major league pitcher."

MDA's director, Lt. Gen. Henry Obering, interprets the GBI test record differently. "Today, we are well beyond the question of `Does this work?'" Obering says. "Every time this kill vehicle has gotten into the endgame, searching for a target, it's been successful. Recently, we've had six out of nine successes in the long-range program. And in those six tests, five were against countermeasures."

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Critics contend that the test decoys were too easy to discover. "We know how to build a balloon in the shape of Mickey Mouse's ears," says Philip Coyle, who served as an assistant secretary of defense from 1994 to 2001. "We can assume that North Korea or Iran can build one in the shape of an ice-cream cone."

Obering claims that future tests will use more advanced decoys and that his agency is developing multiple kill vehicles (MKVs). If the single kill vehicle is a brilliant bullet, MKVs are brainy buckshot, destroying suspicious decoys along with hostile warheads.

Ultimately, the question of whether the GBI is an effective defensive system or simply part of a well-orchestrated bluff could be irrelevant. This year Congress called for a study to determine whether ballistic-missile defense should exist as currently configured, with a review to be finished by 2010. And even if the MDA's $9.3 billion annual budget survives congressional scrutiny, its direction and scope could change under a new presidential administration. For now, Fort Greely is adding more missiles. Stepping out of the silo, I notice the day feels colder. There are 20 silos in this missile field, and in the distance, a silo is hanging suspended from a crane--another missile field under construction. I ask Bond why the inventory keeps growing, when neither North Korea nor Iran has successfully tested an ICBM. "You cannot wait until an enemy has a knife at your throat to figure out how to parry the thrust," he says. "If you do, your life or your wallet will be forfeit."

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Col. George Bond is responsible for the operation of ICBM interceptors stored in climate-controlled silos at Fort Greely, Alaska.

Working on the Edge

Before leaving Greely, I interview Delta Crew, one of the base's five GBI launch teams. Like nearly everyone here, they are full-time Alaska Army National Guardsmen, but they hail from all over the country. When on duty, this five-man crew is responsible for all of the interceptors at the base--they're the ones with their fingers on the proverbial button. They monitor sensor data from around the world and maintain contact with their sister control room in Colorado Springs.

During every 8-hour shift, they run through four to six versions of doomsday. The simulations are different every time. The warhead might eject a new kind of decoy, trying to spoof the ground-based radar. Or the first interceptor could fail in its silo, forcing the immediate launch of other missiles. The crew has to prepare for each system to fail and for every worst-case scenario to get even worse.

Everyone is doing his job simultaneously, regularly reporting back to the team's director, who describes it all as a kind of orchestra. While the sensors operator, 1st Lt. Jason Delange, is talking to a radar installation out in the Aleutian Island chain, the battle analyst, 1st Lt. David Moss, is monitoring incoming intelligence. When they speak to each other, the members of Delta seem to have their own lingo. A hostile launch is a "quick alert." Instead of answering with a yes, they say "check," an artifact of artillery posts, where concise, rapid-fire feedback is essential.

Finally, I ask how they cope with the constant drilling, the minus-50-degree temperatures during the winter and the pressures of this kind of nonstop apocalyptic vigil. Everyone in Delta, to a man, says he loves the job and doesn't want to be anywhere else. And more important, they believe that if a missile is headed for the United States, the MDA's defensive net will work. "I feel confident in the system," says Delta Crew's director, Maj. Don Mercer. "I always tell my wife, `Sleep well at night when I'm on duty.'"

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